Roller contact device for electrical coil



Jan. 19, 1965 E. c. HIGGINS ETAL ROLLER CONTACT DEVICE EoR ELECTRICAL con.

Filed Dec. 4, 1962 4 Sheets-Sheet l E ER EE, E@

@EN uw E Jan. 19, 1965 E Q HlGGlNS ETAL 3,166,368

RLLER CONTACT DEVICE FOR ELECTRICAL COIL.

Filed Dec. 4, 1962 4 Sheets-Sheet 2 Inventors,

By: Z

E. C. HIGGINS ETAL Jan. 19, 1965 Filed Deo. 4, 1962 ROLLER CONTACT DEVICE FOR ELECTRICAL COIL 4 Sheets-Sheet 5 Jan. 19, 1965 E. c. HlGGlNs ETAL 3,166,368

ROLLER CON'IACT DEVICE FOR ELECTRICAL COIL Filed neo. 4, 1962 4 sheets-sheet 4 2f if] f fr 30 mi2!) I Q /7 /4 L .9K6 23 27 [I /6 @Il Lgw N nvenlori.

lfiliiid Patented Jan. 19, T965 3,166,368 ROLLER CONTACT DEVICE EUR ELECTRICAL CIL Edward C. Higgins, 33 Retinal Hill Lane, Rubery, Retinal,

Birmingham, England, and Albert E. Pearson, 75 Tagwell Road, Droitwich, England Filed Dec. 4, 1962, Ser. No. 242,122

6 Claims. (Cl. 339-9) The invention is concerned with electrical contact devices for use with variable transformers and other coils and ofthe kind comprising lone or more contacts adapted to be moved in a path parallel tothe axis of a transformer Winding or other coil while being maintained in conductive contact with the turns of the coil. Such devices are generally described as voltage regulators or simply regulators.

The contact members are usually made of carbon, being commonly rollers, associated with resilient means for maintaining the required contact pressure. Also each contact device usually comprises a pair of such rollers which are co-axially arranged and so mounted that they will automatically adjust themselves so as to lie symmetrically with respect -to -a plane which contains the axis of lthe coil, the common axis of the rollers being substantially normal to that plane.

' It is desirable that such contact devices be mounted in such a manner that the contact rollers or other members will remain positioned positively and accurately with reference to the surface of the coil as they move over that surfaceand will also be readily removable for the purpose of inspection and 'general maintenance. The object of the invention is to provide such a contact device which will be of comparatively simple construction and will possess the'abovementioned desirable qualities.

The invention will now be further described with reference to two examples which are illustrated in the accompanying drawings wherein:

FIGURE l is a plan of a contact device incorporating two pairs of roller contacts.

FIGURE 2 is a view in elevation as seen in the direction ofthe arrow II in FIGURE l.-

Y FIGURE 3 is a sectional View on the line III-III in FIGURE l.

FIGURE 4 is a sectional view on the line IV-IV in FIGUREy 1. f

FIGURE 5 is a sectional view on the line V-V in FIGURE 1Q t FIGURE 6 is -a plan view of another arrangement incorporating a single pair of roller contacts and, n

AFIGURE 7 is a view in elevation as seen in the directionof the arrow VII in FIGURE 6.

VReferring first of all -to FIGURES 1 to 5, the apparatus shown comprises two pairs of roller contacts adapted to engage the cylindrical exterior lof a transformer winding, represented by the broken line 1 having its axis perpendicular to the paper in the case of FIGURE 1. The

roller contact assembly will be movable, by means` the manner described belowLthat the major transverse dimension of the strips extends in a direction parallel with the axis of the winding 1. The forward end of each side arm 3`is formed with a slotS which is parallel-.sided and is adapted to receivethe end of a circulerr-section`v contact-carrying spindle 6;* Mid-way alongits length each spindle 6 is mounted in al metal blockp7 having a rear rod-like extension 8, the end of the rod being slidable in Van aperture located centrally in the base 4 of the U-shaped member 2. The spindle 6 is held against rotation relatively to the block 7 with which it makes a conductive joint, for instance a soldered joint. The coiled spring 9 surrounds the rod-like extension 8 and bears at its forward end against the abutment provided by the end of the metal block 7 and at its rear against the inside. of the base member 4 of the U-shaped frame 2. TheI diameter of the spring 9 is greater at its rear end than at its forward end so that the unit structure comprising the contact-carrying spindle 6 and its mountingr is permittedk to have a certain degree of pivotal movement while at the same time the larger end Yof the spring 9 in contact with the base member 4 of the bracket 2 provides a desirable stability of the support. The rear end of the spring is conveniently located in a shallow recess in the base of the U-shaped frame.

The U-shaped frames 2 are .so mounted by means described below that they are inclined to one another with their 1axes of symmetry extending radially with respect to the axis' of the transformer winding 1.

On each spindle 6 there are rotatably mounted .two carbon contact rollers 1d, located one on each side of the block 7 and each `formed with a central bushing 11, FIG. 5, of brass or other wear-resisting conductive metal. The outer ends of the bushings 11 are formed with relatively' thin radial fins 12 which provide cooling surfaces.

The blocks 7 may each also be formed with external ribs and( or recesses extending in plane normal to the axis of the -spindle 6 and also serving to assist cooling. The two nearest of the sides 4of the U-shaped brackets 2 are fastened to a locating member 13 which is in the form of a transevrse web which rigidly joins the two frames 2 together and extends in a plane which is substantially parallel with the axis of the coil 1. As indicated in FIGURE l this locating member 13 is of an appropriate shape to ymaintain the frames 2 mutually inclined to one'another las described above.

The contact device is mounted on an insulating llat base plate 14 by means of U-shaped bracket 15 consisting of an elongated generally U-shaped member of which one arm 15a is fixed to the base plate 14. The base of the bracket extends normal to the base plate in a plane parallel with both the coil axis and with atangent to the coil." The bracket 15 is so arranged that the mouth of the U-shaped formation faces the forward edge of the FIGURES l and 4. The springs 9 tend to maintain the roller'contacts lll in engagement'with the winding 1 and at the same time to press the locating member 13 tirmly into place in the bracket 15. To release the device from the base plate 14 it is first necessary to displace the loeating member 13 towards the transformer 11 against the spring pressure and into a position in which it is clear of the bracket 15 and can be lifted olf the base plate 14.

' The insulating base plate iis mounted on the upper surface of a metal carrier plate 16 which constitutes part of a supporting frame. The carrierv plate is associated atl both ends, only one of which is shown, with a'ariage 19 on which are mounted guide rollers in engagement with `fixed guide rails 21 to enable the whole device to be moved in. a direction parallel with the axis of the-trans .v former winding 1 by any appropriate mechanical driving dividual transformer winding positions. assembly is readily disengageable' from the insulating arrangement.V The base plate 14 is adjustably mounted on the carrier plate lle byomeans of bolts 17 extended through open-ended slots 13 in the base plate 14, the bolts serving as clamping members.

In a central position behind the bracket the insulating base 14 is provided with an open-ended slot 22 through which freely extends a substantially rectangular section conductive terminal bar 23. This bar 23 also extends freely through an' opening 24 in the'lower carrier plate 16. The bar Zwill be supported'bymeans which are not shown and which do not constitute part of this invention. The base members 4 of the U-shaped rollersupporting frames 2 are formed with'extensions 25 which project towards one another and in mutual alignment behind the bracket 15. Each extension 25 has mounted on itsrear face and has conductive engagement with a short open-ended rectangular-section tubular brush holder 26 adapted t'o receive a corresponding rectangular-section brush 27. Tension springs 28 anchored to the brush holders 26 and engaging the outer ends of the brushes Z7 urge the. brushes into conductive contact with opposite faces of the terminal bar 23. To the rear end of each of the rod-like extensions S there is attached by means of a screw 3d a terminal tag 3l and the terminal tags are connected to the appropriate brushes by means of ilexible conductive `leads 29. Alternatively the flexible leadsocan be connected to the actual brush holders 26. The terminal tags 31 are Valso adapted to prevent the rodlike members 8 from being completely forced out of their engagement with the base members 4 ofthe frames 2 by the springs 9 and also, as is apparent in FIGURE 1, to prevent the brushes 27 from being moved completely out of en- Y gagement with the brush holders 26. Y

Referringnow to FIGURESy 6 and 7, the contact assembly thereshown comprises only a single pair of rollers; Suchparts of the arrangement shown in these figures which are substantially similar to those already described are for convenience indicated by the same reference numbers. In this arrangement the U-shaped rollencarrying frameis provided with'two L-section locating members fixed to the outsides of thel side arms 3. Each locating member comprises one arm 32 which is iixed to and lies in close engagement with the side arm and a locating arm 33 extending at right angles to the side'arm and engaging in a locating bracket 15. The locating brackets 15 are substantiallythe same as those already described, being fixed on the insulating base plate, one on each side of the contact-carrying frame. In this arrangement the spring 34 which controls the pressure of the roller contacts on the transformer winding and also the engagement of the CIK locating members with the brackets 15, is of uniform di-V ameter and at its forward end seats inV a shallow dish washer 35 which itself abuts against the back of the block There is in thisarrangement only one brush assembly in engagement with one face of the contact bar The .washers 36 indicated and 7 there may bemounted on a common carrying plateV for engagementV with a corresponding member of transformer windings. n

The invention has a number of advantageous features. For instance it permits of alimited but appropriate degree of lateral movement of the'contact assemblies to suit in- Each .Contact base 14 without it being necessary to manipulate screws` or the glikeythe quick-release feature permitting easy removal for such purposes as inspection, renewal, and general maintenance. n i l It will'be appreciated that a comparatively directgcond ductive path is provided for the passage "of current from each roller contact to the terminal bar 23. Other advantageous features will be evident from the above description of the invention.

What we claim then is:

l. An electric contact device for traversing a path parallel with the axis of a coil and including av frame; a contact member movably mounted in the frame for contactA with the exterior ofthe coil, a spring interposedbetween the frame and the Contact member to bias the latter towards said axis, an insulating base plate lying in a plane to axis to support the frame, and mounting means for supporting and locating the frame on the plate; the mounting means comprising U-shaped .bracket means mounted on the plate and opening towardssaid axis,n the bracket means having opposed spaced limbs and a base ioining the limbs, the limbs lying in parallel planes lnormal to the axis and the base lying in a plane which is parallel both to the axis to a tangent to the coil, the mounting reans also comprising a locating member onthetrame received in the bracket means and forced into contact with said base by saidspring when the contact member engages the coil thusl limiting outward movement of. the

framerelative to the axis, the locating member also engaging between said limbs to provide location of vthe frame axially of the coil, movement ofthe frame againstV allel with the axis of a coil and including two frames, two' contact members each movably mounted in one of the iframes for contact with the exterior of the coil, a spring interposed between each frame and the contact member mounted therein to bias the latter towards said axis, an insulating base plate lying in a plane normal to said axis to support the frames, and mounting` means for supportingv and locating the frames on the plate; the vmountingV means. comprising Uashaped bracket' means mounted on the` plate and opening towards said axis, the bracket means havingopposed spaced limbs .and 4a base joining the limbs, the limbs lying in parallel planes normal tolthe'axis and the base lying in a plane which is parallel both to the axis and to a tangent to the coil, the mounting means also comprising a locating member extending between, and uniting the frames, the locating member being received in thel bracket means and forced into contact with said base by said springs when the contact members engage the coil thus limiting outward movement ofthe frames relative to the axis, the locating member also engaging between said limbs to provide location of the frames axially of the coil, movement of frames against the springs permitting disengagement of the locating member from the bracket means and dismounting of theV frame from vthe base plate.

3. An electric contact device as claimed in claim 2 in which the frames have axes of symmetry which are mutually convergent so as to extend radially withrespect to said axis, and each of said springs is a coiled compressed spring located with its axis coincident with the axis of symmetry of the frame in which it is incorporated. 4. A device according4 to claim 2, wherein each frame is U-shaped having slots in the end portions ofthe arms of the U and wherein eachl contactv member comprises two contact rollers, there being associated with each frame supporting spindle means having its `ends received in said slots and supporting said rollers, an electrically conductive member providing at one enda mountingl aperturerin the base of the U-shaped frame, an abutment on the member adjacent the mounting and a compression the abutment and the base*v of the frame. -2

5. An electric contact device for traversing a path parallel with the axis of a coil and including a frame; a con- -tact member movably mounted in the frame for contact with the exterior of the coil, a spring interposed between the frame and the contact member to bias the latter towards said axis, an insulating base plate lying ina plane normal to said axis to support the frame, and mounting means for supporting and locating7 the frame on the plate; the mounting means comprising two U-shaped bracket means mounted in spaced relation on the base pla-te and each opening towards said axis, each bracket means having opposed spaced limbs and a base joining the limbs, the limbs of each bracket means lying in parallel planes normal to the axis and the bases of the bracket means lying in parallel planes each of which is parallel bothy to the axis` and to a tangent to the coil, the mounting means also comprising two locating members secured to opposite sides of the frame and each received in one of the bracket means and forced against the base of its associated bracket means by said spring when the contact member engages the coil thus limiting outward movement of the frame relative to the axis, each locating member also engaging between the limbs of its associated bracket means to provide location of the frame axially of the coil, movement of the frame against the spring 25 permitting disengagement of the locating member from the bracket means and dismounting of the frame from the base plate.

6. A device according to claim 5, wherein the frame is U-shaped having slots in the end portions of the arms of the U and wherein the contact member comprises two contact rollers, there being associa-ted with the frame supporting spindle means having its ends received in said slots and supporting said rollers, an electrically conductive member providing at one end a mounting for the spindle and extending therefrom centrally between and parallel to the arms of the U-shaped frame to the o-ther end or" the member which is slidable in an aperture in the base of the U-shaped frame, an abutment on the member adjacent the mounting and a compression spring surrounding said member and interposed between the abutment and the base of the frame.

References Cited by the Examiner UNITED STATES PATENTS 3/56 Gray 339-9 2,757,348 7/56 Gray et al. 339-9 FOREIGN PATENTS 834,349 5/ 60 Great Britain.

JGSEPH D. SEERS, Primary Examiner. 

1. AN ELECTRIC CONTACT DEVICE FOR TRAVERSING A PATH PAALLEL WITH THE AXIS OF A COIL AND INCLUDING A FRAME; A CONTACT MEMBER MOVABLY MOUNTED IN THE FRAME FOR CONTACT WIHT THE EXTERIOR OF THE COIL, A SPRING INTERPOSED BETWEEN THE FRAME AND THE CONTACT MEMBER TO BIAS THE LATTER TOWARDS SAID AXIS, AN INSULATING BASE PLATE LYING IN A PLANE NORMAL TO SAID AXIS TO SUPPORT THE FRAME, AND MOUNTING MEANS FOR SUPPORTING AND LOCATING THE FRAME ON THE PLATE; THE MOUNTING MEANS COMPRISING U-SHAPED BRACKET MEANS MOUNTED ON THE PLATE AND OPENING TOWARDS SAID AXIS, THE BRACKET MEANS HAVING OPPOSED SPACED LIMBS AND A BASE JOINING THE LIMBS, THE LIMBS LYING IN PARALLEL PLANES NORMAL TO THE AXIS AND THE BASE LYING IN A PLANE WHICH IS PARALLEL BOTH TO THE AXIS AND TO A TANGENT TO THE COIL, THE MOUNTING 